I puchased a Retention Dorado Max 48v 20.4 A 500W battery from Susie in August. It fit and works perfectly on my 2018 Surface Colt. I am north off 300lbs and the stock 10.4A just did not cut it for me. With this battery I can now get close to 50 miles on a charge. Just make sure you order a 5 pin output port. I live in Vancouver, B.C. and there are a lot of hills on the mountain side of the city so I usually ride in
level 3 assist. My experience with Susie was absolutely fantastic she repied to emails promptly and sent pictures to ensure I was getting the right battery for my bike. I don't know why anyone would give her a hard time. There is no difference between this battery and the one that came with the bike. The only difference is that the 20A was less expensive than the 14A that Surface offers. Don't let the nay sayers put you off dealing with Susie as she is a lot easier to deal with than people here. So what if she lives in China it is a global world now with Amazon and Alibaba. If someone is on this forum bashing Susie it is because they are having trouble ripping people off for the batteries they are sell. I would suggest they get them from her and offer them here for a reasonable price. It is not rocket science buying direct from China and through Alibaba you have assurance that you will get what you ordered. Thanks for everything Susie you are a pleasure to deal with.